Ah, okay now I know what "The Book About Moomin, Mymble and Little My" is, it's another picture book, also very beautiful! The catch in that book is that there's always a hole in each page, showing something from the next/previous page spread, and the hole is integrated into the art and story, so the characters are following the wholes from one spread to another.
― Tuomas, Saturday, 31 January 2015 00:42 (nine years ago) link